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Topic: Stroke (engines)

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	Four-stroke - Wikicars
		The power output of the engine is dependent on the ability of the engine to allow large volume flow of both air-fuel mixture and exhaust gas through the respective valve ports, typically located in the cylinderhead.
		Rod/stroke ratio is the ratio of the length of the connecting rod to the length of the crankshaft's stroke.
		An engine where the bore dimension is larger than the stroke is commonly known as an oversquare engine, and such engines have the ability to attain higher RPM.
	wikicars.org /en/Four-stroke (2186 words)

	Two-stroke cycle - Wikipedia, the free encyclopedia
		These engines commonly also use a crosshead bearing, which together with a sliding seal on the piston rod allows the air path to be separated from the crankshaft while still using the piston movement as an air pump.
		The simpler stroke in the fully valved diesel two-stroke cycle is the compression stroke; both valves are closed, and the rising piston compresses the air, heating it.
		Two-stroke engines have several marked disadvantages that have largely precluded their use in automobiles (although there was some use, such as in historic Saabs and DKWs and until recently in several automobiles produced in the Eastern bloc, including Trabants and Wartburgs, among others) and are reducing their prevalence in the above applications.
	en.wikipedia.org /wiki/Two-stroke_cycle (2296 words)

	MSN Encarta - Internal-Combustion Engine
		Four principal types of internal-combustion engines are in general use: the Otto-cycle engine, the diesel engine, the rotary engine, and the gas turbine.
		At the moment when the piston reaches the end of this stroke and the volume of the combustion chamber is at a minimum, the fuel mixture is ignited by the spark plug and burns, expanding and exerting a pressure on the piston, which is then driven away from the cylinder head in the third stroke.
		The fourth stroke, as in the Otto-cycle engine, is an exhaust stroke.
	encarta.msn.com /encyclopedia_761553622/Internal-Combustion_Engine.html (1498 words)

	Encyclopedia article: Two-stroke cycle (Site not responding. Last check: 2007-10-25)
		The design types of the two-stroke cycle engine vary according to the method of intake of fresh air/fuel mixture from the outside, the method of scavenging the cylinder (A surface generated by rotating a parallel line around a fixed line) (exchanging burnt exhaust for fresh mixture) and the method of exhausting the cylinder.
		Two stroke engines mix lubricant with their fuel (either manually at refueling or by injecting oil into the fuel stream); this mixture lubricates the cylinder, crankshaft and connecting rod bearings.
		These engines commonly also use a crosshead bearing (additional info and facts about crosshead bearing), which together with a sliding seal on the piston rod allows the air path to be separated from the crankshaft while still using the piston movement as an air pump.
	www.absoluteastronomy.com /encyclopedia/t/tw/two-stroke_cycle.htm (2303 words)

	Stroke (disambiguation) - Wikipedia, the free encyclopedia
		Stroke in medicine, a cerebral accident, when blood supply to a part of the brain is suddenly interrupted.
		Stroke (Chinese character), in graphics of Chinese characters.
		Stroke (engines), a single action of some engines.
	en.wikipedia.org /wiki/Stroke_(disambiguation) (133 words)

	Internal Combustion Engines
		An engine is defined as the machine that converts the chemical energy liberated through combustion of a certain fuel, into a mechanical energy that is used to derive a certain vehicle.
		As previously mentioned, the main difference between the engines are either the number of strokes or the cycle that is used to ignite the fuel.
		In other words, the only difference between is the Otto engine and diesel engine is that the latter does not require a spark plug to ignite the fuel; the fuel here is ignited under the effect of increase in pressure and temperature.
	biotsavart.tripod.com /ice.htm (2224 words)

	Engines Physics 104 - University of Maryland
		In modern engines the 'compression ratio' is about 8 to 1, meaning the entire contents of the combustion chamber is compressed into an area of about one eighth of its original size.
		The general principle of the two-stroke engine is to shorten the periods in which fuel is introduced to the combustion chamber and in which the spent gases are exhausted to a small fraction of the duration of a stroke instead of allowing each of these operations to occupy a full stroke.
		In the simplest type of two-stroke engine, the poppet valves are replaced by sleeve valves or ports (openings in the cylinder wall that are uncovered by the piston at the end of its outward travel).
	umdgrb.umd.edu /~goodman/engines/engines.html (612 words)

	Howstuffworks "How Car Engines Work"
		Diesel engines are one form and gas turbine engines are another.
		A steam engine in old-fashioned trains and steam boats is the best example of an external combustion engine.
		A car engine is one of the most amazing machines we use on a daily basis.
	auto.howstuffworks.com /engine.htm (701 words)

	AMPS - Engines Guide - Glow Engines
		All glow engines require a special fuel, called "glow fuel." It consists of methanol as base, with some amount of nitromethane to increase the energy and pre-mixed oil into the fuel, which lubricates and protects the engine parts.
		In a four-stroke engine the fuel/air mixture enters the combustion chamber during the down movement of the piston through a valve operated by the camshaft (1st stroke).
		When the engine is in the upright position, the fuel tank's centerline should be at the same level as the needle valve or no lower than 1cm, (3/8in) to insure proper fuel flow.
	www.amps-rc.com /Library/Engines/GlowEngines.htm (1227 words)

	Animated Engines Two Stroke Cycle
		The two stroke engine employs the crankcase as well as the cylinder to achieve all the elements of the Otto cycle in only two strokes of the piston.
		During the downward stroke the poppet valve is forced closed by the increased crankcase pressure.
		Unfortunately most two stroke engines are inefficient and are terrible polluters due to the amount of unspent fuel that escapes through the exhaust port.
	www.keveney.com /twostroke.html (283 words)

	Carbureted 2-stroke Marine Engines: (Site not responding. Last check: 2007-10-25)
		This is because DFI 2-stroke and 4-stroke marine engines use technology that significantly, 75% to 95%, reduces the amount of HC+NOx that are exhausted from the engine.
		The difference between a 2-stroke and 4-stroke engine is in the number of piston strokes used to intake the fuel, compress and ignite it, and exhaust - this is called a power cycle.
		San Jose, CA adopted regulations on conventional marine engines for the Calero Reservoir because it is a source of drinking water for the population of San Jose.
	www.deq.state.or.us /programs/P2/reports/marine_engines.html (8808 words)

	The marine diesel prime mover. - The two stroke plant
		The two stroke and four stroke titles refers to the mechanical action of the machinery, in particular the piston within the cylinder, to achieve the theoretical Carnot heat cycle, as define by the laws of thermodynamics.
		The most prominent builders of large, slow speed, two stroke engine are Sulzer of Switzerland, producer of the first big two stroke design, and Burmeister and Wain (BandW) of Denmark, the pioneers of the engine’s application to ship design.
		Two stroke engine have a wide variety of power output from the 353 Detroit Diesel with an output of less than 75 kW to a Sulzer RT-flex96C producing a 80,080 kW or about 109,000 bhp from fourteen cylinders turning at 102 rpm, not to be outdone MAN BandW has come out with the K108ME-C.
	www.dieselduck.ca /machinery_page/diesel_engine/diesel_engine.01.htm (1471 words)

	Laser Engines
		The engine in every motor car is a 4-stroke and even the small engines for strimmers (weed wackers) are changing from 2-stroke to 4-stroke to meet the latest noise and exhaust emission requirements.
		The valves are inclined to the rear of the engine reducing the height of the engine.
		As the engine warms up the steel bolts tighten further against the expansion of the aluminium cylinder so it is impossible for a the cylinder head to come loose when the engine is running.
	www.laserengines.com (1343 words)

	2 stroke and 4 stroke engines
		A 4 stroke engine usually has a distributor that supplies a spark to the cylinder only when its piston is near TDC on the compression stroke, ie.
		Take for example the lubrication issue of 2 stroke engines, sure small chainsaw engines may have the oil mixed with the fuel but this is not a direct result of the engine being a 2 stroke, this is just a result of someone designing a very simple engine.
		The 2-stroke engine does have channels for air transport but the piston opens and closes the channels, in a 4-stroke engine there are seperate valves and a camshaft that do this.
	www.deepscience.com /articles/engines.html (1507 words)

	Epinions.com - 2-stroke engines? dead? i dont think so
		We all know what a 4 stroke engine is, thats the type of engine you find in your average car or van.
		The design of this engine is much more lightweight and less complex than that of the 4 stroke due to the fact it doesnt need valves, springs, camshafts etc, as it uses a system commonly known as 'ports'.
		You can usually tell which type an engine is by the colour of the exhaust, a 2-stroke will pump out blue smoke, and usually quite a bit of it, where as a 4-stroke doesnt, (unless it has a problem).
	www.epinions.com /content_1682088068 (863 words)

	03-Two-Stroke Engine Technology Brochure
		Capacitive sensors are multiplexed to an oscillator that transmits temperature data as an RF signal to an antenna in the engine sump.
		A piston is instrumented to measure seven temperatures simultaneously in a turbocharged engine.
		In a novel and robust design adaptable to production engines, an optical spark plug probe and a head gasket ionization probe are being combined to facilitate the study of early flame kernel development, growth, and completion of combustion.
	www.swri.org /3PUBS/BROCHURE/D03/stroke/stroke.HTM (978 words)

	R/C Nitro Touring Car Racing Page
		On 4-stroke engines, timing is controlled by the cams that open and close the valves at predetermined sequences to bring a fresh air/fuel charge in and to exhaust it out the manifold.
		Engine builders try to stay within a certain range for both the intake and the exhaust timing of an engine for reliability and ease of tuning.
		The speed at which the pressure waves from the pipe synchronizes with the piston, is a function of the length from the belly of the tuned pipe (widest part) to the center of the glow plug.
	www.nitrorc.com /articles/2strokepart1a.html (2994 words)

	Howstuffworks "How Two-stroke Engines Work"
		Both gasoline and diesel automotive engines are classified as four-stroke reciprocating internal-combustion engines.
		There is a third type of engine, known as a two-stroke engine, that is commonly found in lower-power applications.
		In this article, you'll learn all about the two-stroke engine: how it works, why it might be used and what makes it different from regular car and diesel engines.
	www.howstuffworks.com /two-stroke.htm (148 words)

	STIHL - STIHL 2-stroke engines - tomorrow's 2-stroke technology from STIHL (Site not responding. Last check: 2007-10-25)
		Unlike 4-stroke engines, which can normally only be operated in one position on account of the separate oil circulation and engine oil reservoir, STIHL 2-stroke engines are reliably lubricated by the fuel mixture in absolutely every working position.
		STIHL 2-stroke engines are superior to conventional 4-stroke engines as regards the advantageous power-to-weight ratio, high torque over a large speed range, compact engine with few components, low maintenance requirements and easy servicing.
		The basic design principle is the only thing that today's consistently improved 2-stroke engines from STIHL have in common with the first generation of 2-stroke engines and their high intensity of emissions.
	www.stihl.com /knowhow/producttechnics/stihlengines/2_stroke/default.htm (433 words)

	Shindaiwa \| Technology \| C4 Technology
		The end result is an engine with the outstanding performance, reduced noise and fuel consumption and extremely low levels of exhaust emission.
		However, large 2-stroke engines, with their high fuel consumption, had a non-compatible powerband and proved ineffective for their direct drive, propeller-driven aircraft.
		With its cylinder ports to transfer fuel/oil mix, the typical 2-stroke engine performs with a power stroke with every two strokes (one revolution of the crankshaft) of the piston.
	www.shindaiwa.com /nam/en/technology/c4/index.php (1081 words)

	Two-stroke and Four-stroke Engines (Site not responding. Last check: 2007-10-25)
		The fuel is ignited (by a spark in a gas engine, by being injected into high temperature air in a diesel.) The energy released drives the piston down.
		Because a 2-stroke engine gets a power stroke twice as often as a four-stroke engine, it puts out about twice as much power (and makes twice as much noise) as a four-stroke engine of the same size.
		So 2-stroke engines are used in chainsaws and lawnmowers, where power/weight is important, but the engine isn't used for long periods so pollution and engine life are less of a concern.
	robotics.caltech.edu /~mason/ramblings/2stroke4stroke.html (393 words)

	Maintaining Small Engines
		A small engine is an internal combustion gasoline engine that produces less than 40 horsepower.
		A two-stroke or two-cycle engine mixes and compresses in one rotation, then ignites and exhausts during the second rotation or stroke.
		Because small engines don't develop as much heat, they typically are cooled by the surrounding air.
	www.bobvila.com /FixItClub/Task/Repairing/FIG_SmallEngines.html (531 words)

	Four Stroke?
		The only real engineering difference is the SY engines, Magnum, ASP, and others, have true chrome plating in their cylinder liners while OS is using nickel plating.
		OS has had problems with the nickel peeling in their two stroke engines, I've not heard of a problem in the 4s engines, but it is one thing that puts me off OS.
		The only OS engines that are not matched or exceeded by another maker is their flat four cylinder Pegasus, and the Wankel 30.
	www.rcuniverse.com /forum/fb.asp?m=1878302 (2048 words)

	Montana DEQ - Clean Snowmobile Facts - Solutions - Two-Stroke Engine Modifications
		Substituting rotary four-stroke engines for two-stroke engines to maintain power-to-weight ratios of the two-stroke engine.
		A promising technology that would improve two-stroke engine efficiency and reduce emissions is the Smart Plug, which, in effect, transforms a catalytic converter into the equivalent of a spark plug.
		When the catalyst is sufficiently heated and the engine's fuel-air mix is pumped in, courtesy of the starter motor, the catalyst sets fire to the small amount of charge inside its body, and the flaming charge then blasts out the holes, into the combustion chamber, and the piston goes down.
	www.deq.state.mt.us /CleanSnowmobile/solutions/engine/modifications.asp (878 words)

	BBC - h2g2 - Two-Stroke Engines
		A two-stroke engine is the little brother of the four-stroke engine.
		In other types of engines, the crankcase is filled with oil for the purposes of cooling and lubrication.
		In addition to other things, the lack of valves in the cylinder means that, during the compression stage, some of the mixture leaks out the exhaust port.
	www.bbc.co.uk /h2g2/guide/A650918 (408 words)

	Two-Stroke Neon Engines?
		In addition to being larger, the Phase 3 engines had a balance shaft rotating at the speed of the crankshaft (unlike the 2.5 liter 4s, which rotate at twice the speed).
		Four-stroke DI gas engines are believed to have the potential of one day achieving more than 45 miles per gallon, which is comparable to advanced, small displacement direct injected diesel engines of the future.
		Two-stroke engines have long been promising because of better fuel economy, fewer parts, better efficiency and a smaller engine package (about two-thirds the size and weight of conventional engines) that would allow for more design flexibility and lower hood lines.
	www.allpar.com /neon/stroke.html (1199 words)

	[No title]
		Northeast Ohio Stroke Activity Center - One of three centers in the USA that is organized to bring state-of-the-art rehabilitation to stroke survivors and their families in need of such services.
		Stroke and Cerebrovascular Diseases - Stanford Stroke Center's extensive, illustrated guide for stroke patients and their families.
		Stroke Rehabilitation in the Elderly - Doctoral thesis by Kauko Pitkänen, focusing on long-term rehabilitation for survivors aged 65 and older.
	www.diseasedirectory.net /Neurological_Disorders/Stroke/default.aspx (1761 words)

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